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M R Bobkova

Publications and source records attributed to M R Bobkova.

At least 19 recordsLinked to original sources
PubMed2002

[Molecular genetic characteristics of HIV-1 in Russia].

The paper presents data on the variants of human immunodefficiency virus type 1 (HIV-1) currently circulating in Russia. The subtype A HIV-1 variant dominating is shown to be most widespread among drug-injected users in the most regions under study. By using the results of an analysis of 1,464 blood samples taken in the past 4 years in 69 subjects of the Russian Federation, the authors have estimated that this HIV-1 variant is responsible for 93% of all HIV-infection cases in the country. The greatest regional genetic diversity was observed in Moscow and its mean (2.35(1.59) was found to be comparable to that (2.41(1.85) in the whole country. Penetration of the subtype A IV-1 variant early detectable among drug-users into other risk groups was noted.

HIV Infections↗
PubMed2001

Serological approaches to subtyping of HIV-1 in injecting drug users in Russia: evidence of subtype homogeneity at the main sites of the epidemic.

The aim of this study was to develop and evaluate a simple V3 peptide-based enzyme immunoassay (PEIA) for large-scale serotyping of HIV-1 specimens derived from injecting drug users (IDUs) in the Russian Federation. Two synthetic peptides were evaluated, named P1 (RKSIHIGPGRAFYATGD) and P2 (RTSVRIGPGQVFYKTGD), in an PEIA on 63 HIV-1 IDUs sera for which genotypes had been determined by heteroduplex mobility assay (HMA) and sequencing. The sensitivities of P1 (subtype B) and P2 (subtype A) were 87% and 75% respectively. Specificity of the assay was 100% for both peptides, with 100% predictive values of a monoreactive positive test for both peptides. Using the PEIA with peptides P1 and P2, we have serotyped 375 of 477 serum samples derived from IDUs in 4 main sites of the HIV-1 epidemic in Russia. The results demonstrated a high level of subtype homogeneity in all regions studied. In 3 of 4 territories, Tver' (n=345), and Rostov-on-Don (n=61) regions, and Krasnodar Kray (n=27), 100% of typable sera were found to belong to env subtype A. On the other hand, all specimens serotyped in the Kaliningrad region (n=38) belonged to env subtype B, and there is strong evidence that the recombinant gagAenvB virus which has caused the largest outbreak of HIV-1 in Russia is located in this region. At the present time another parental strain with gagBenvB genotype is of minor importance in the IDUs HIV-1 epidemic in Russia.

Amino Acid Sequence↗
PubMed2000

[Expression of a fragment of the env gene, coding for the GP46 surface glycoprotein of the human T-cell leukemia virus, in Escherichia coli cells].

Designing of recombinant plasmids pSB2 and pSB3 with the 932 bp HTLV-II env gene inserts encoding the full-length surface membrane glycoprotein gp46 is described. Vectors pGOmpF and pET32a expressing genes cloned under control of the late bacteriophage T7 promoter were used. Western blot analysis of cellular proteins derived from E. coli B834/pSB2 and E. coli B834/pSB3 revealed that 34 kD and 31 kD polypeptides corresponding to the full-length gp46 and its processed form without signal peptide were synthesized under control of these recombinant plasmids. Cytotoxic activity of the recombinant proteins towards bacterial cells was demonstrated. Both polypeptides specifically reacted to sera from humans infected with HTLV-II. High antigenic specificity of P34-HTLV-II proteins makes a promising candidate for diagnostic confirmation tests.

Base Sequence↗
PubMed1999

[Clinico-laboratory characteristics of acute viral hepatitis C in parenteral drug addicts].

AIM: To study clinical and laboratory manifestations of acute viral hepatitis C in parenteral drug addicts. MATERIALS AND METHODS: Acute viral hepatitis C (AVHC) was diagnosed in 114 patients included in the trial by serological evidence and virus RNA determination at polymerase chain reaction. Among the examinees there were 63 addicts and 51 non-addicts. RESULTS: In addicts, AVHC manifests with pain in the liver, anorexia, moderate intoxication, hepatomegalia, abstinence syndrome. At admission most the addicts had a moderate rise in bilirubin concentration with prolonged normalization. 25% of the addicts had ALT < 1400 micromol/l/h, its lowering was slow. In convalescence, the addicts' liver long remained enlarged, concentrations of ALT, alkaline phosphatase, GGT remained high. CONCLUSION: VHC runs a moderate course in parenteral drug addicts, shows polymorphic symptomatology, hepatomegalia, high blood levels of ALT. Convalescence is long, hepatic functions recover slowly.

Acute Disease↗
PubMed1990

[Cloning and expression of the gene for diphtheria toxin and its subunits in Escherichia coli].

The results of cloning Corynebacterium diphtheriae phi 984 tox gene and its A and B subunits in Escherichia coli are presented. Regulatory sequences of tox gene are capable to promote effective expression in E. coli cells. A set of recombinant plasmids has been obtained which can determine the synthesis of A and B individual subunits and are suitable for constructing immunotoxins by gene engineering. The diphtheria toxin of 62 kDa synthesized in E. coli has enzymatic activity and reacts with antitoxin sera. Some sites for E. coli proteases are present in tox-specific polypeptides.

Bacterial Proteins↗
PubMed1989

[The use of DNA fingerprint analysis for the differentiation of populations of toxigenic Corynebacterium diphtheriae].

13 C. diphtheriae strains were used as a model to establish the conditions of making the fingerprint analysis of chromosomal DNA. These strains, subdivided into 7 groups in accordance with the character of their restriction splitting, were mostly isolated from territorially close sources and belonged to the same phagotype. Probably, C. diphtheriae DNA has strain variations manifested by an unequal number and location of the sites of the recognition of specific endonucleases, which may be used for the intraspecific differentiation of C. diphtheriae.

Bacteriophage Typing↗
PubMedDate not supplied

[HIV-1 subtypes in Russia in 1987-1988].

The subtyping of 350 isolates of HIV-1, isolated on the territories of 38 subjects of the Russian Federation, was carried out. The analysis was made by the method of the comparative heteroduplex mobility assay, as well as by the determination of the sequence of genes env [correction of ens] (gp 120) and gag (p17-p24). The study revealed that more than 50% of all cases of HIV-1 infection were caused by closely related variants of subtype A virus. The number of cases of HIV-1 infection caused by recombinant virus A/B was not less than 25%. The total number of cases caused by viruses of subtypes C, D, E, F and H was not more than 5%.

Base Sequence↗